It will probably happen at some point. In my case, it happened the very first time we cloth diapered my tiny newborn daughter—your child poops, you run the diaper through the wash, and it comes out stained! Many people feel gypped the moment this happens. After all, if you have 12 fancy all-in-one diapers that cost $25 each, you will probably panic a bit—they were SO expensive! The Internet swore they were top of the line diapers, and after one use they look used and gross! What to do? (Unless you’re one of the mysterious minorities of parents online who claim that in their nine years of cloth diapering, they’ve left dirty diapers lying around for days before washing and never had a single stain. In that case, you can go on washing your diapers in your magic washing machine and send the magic our way.)

A: “Oh, just put them outside in the sun for a while. It will bleach them to white again!”

This is great advice, unless you don’t have a yard and “putting them outside” will result in them being stolen, eaten by a stray dog passing by, or run over by a city bus three minutes later. What are us apartment dwellers to do?

The city bus: Not a friend of cloth diapers

Thankfully, the sun is pretty much everywhere. I suppose if you are trying to cloth diaper a child in Antarctica, sunning may be impossible for several months of the year, but then your kid is probably out frolicking with penguins as you read this, so I’m actually jealous.

The most common response to “How do I sun my diapers indoors?” is simply, “Put them in a window!” I wish it were that easy. We’re about to get a little scientific here, so bear with me a moment. Sun bleaching works because the sun’s ultraviolet rays disrupt and break down/change the chemical bonds that the ultraviolet rays hit (remember from 5th grade science class, all color we see is just our brain’s interpretation of light being absorbed or reflected off objects). This is also why your plastic outdoor toys fade in the sun; the chemical components that make a plastic slide red are slowly destroyed by ultraviolet rays over time and the bright red slide fades to a weird light red-orange color. Of course, those powerful rays also lead to sunburn, skin cancer, and a host of other issues for humans over time, so in the interest of public health, companies have tried to develop ways to reduce our UV exposure in our daily lives.